The present invention relates an occupant weight sensing system suitable for a vehicle occupant restraint system.
It is known to provide a passive restraint system, such as a seat belt, to restrain a vehicle occupant. Another known restraint system is an active restraint system, such as an inflatable system. The inflatable restraint system typically includes an air bag stored in a housing module within an occupant compartment in the automotive vehicle, in close proximity to either a driver occupant or one or more passenger occupants. The air bag includes an inflation device and an impact sensing mechanism that deploys the air bag. During deployment, gas is emitted rapidly from the inflation device to deploy and expand the air bag at a predetermined rate to a fully inflated state.
Although the above air bag has worked well, the fixed expansion rate of the air bag does not compensate for variations in occupant size. One technique of compensating for variations in occupant size is to measure occupant size, and adjust the deployment rate accordingly. For example, the weight of the occupant can be estimated using a measuring device such as a strain gauge or a load cell mounted in a load path between the seat and a floor of the vehicle. Another type of measuring device is a fluid-filled bladder placed within the seat. While these types of measuring devices work well, it is desirable to provide a less expensive and more general measuring device which is not specific to a particular style of seat. Thus, there is a need in the art for an occupant weight sensing system that is independent of the type of seat, and accurately correlates with the weight of the occupant.
It is, therefore, one object of the present invention to provide a weight sensing system that determines the weight of an occupant through seat frame loading. It is another object of the present invention to use a strain gauge to measure a load on the seat frame.
To achieve the foregoing objects, the present invention is a weight sensing system for use in a seat disposed within an occupant compartment of a vehicle. The weight sensing system includes a measuring device positioned on a seat frame of the seat for measuring a strain on the seat frame due to a seated occupant weight.
One advantage of the present invention is that a weight sensing system is provided for a seat that utilizes a strain gauge mounted to a frame portion of the seat to measure the weight of the occupant through seat frame loading. Another advantage of the present invention is that the load applied to a seat suspension of the seat by the occupant can be directly correlated with the weight of the occupant. Still another advantage of the present invention is that the weight sensing system, including the strain gauge, can be incorporated on many different styles of seat frames with minimal modification.
Other objects, features and advantages of the present invention will be readily appreciated as the same becomes better understood after reading the subsequent description when considered in connection with the accompanying drawings.